Prefabricated section of a wall,floor or roof



Dec. 23, 196.9 c. VAN DER LELY PREFABRICATED SECTION OF A WALL, FLOOR OR ROOF Original Filed Sept. 22, 1964 l 16 Sheets-Sheet 1 Dec. 23, 1969 c. VAN DER LELY 3,484,999

PREFABRICATED SECTION OF A WALL, FLOOR 0R ROOF Original Filed Sept. 22, 1964 INVENTOR Coon/Eu: VAN 05R [ELV Original Fild Sept. 22, 1964 23, 1969 c. VAN DER LELY 3,484,999

PREFABRICATED SECTION or A WALL, LFLOOR on ROOF 1s Sheets-Sheet s INVENTOR Gav/mu: nan/05 [av Wfajwwmfga i 3, 1969 c. VAN DER LELY 3,484,999

PREFABRICATED SECTION OF A WALL, FLOOR OR ROOF l6 Sheets-Sheet 4.

Original Filed Sept. 22, 1964 INVENTOR Gum/51.1; wvv DEA [ELF Wm %M 4% Dec. 23, 1969 c. VAN DER LELY PREFABRICATED SECTION OF A WALL, FLOOR OR ROOF I 16 Sheets-Sheet 5 Original Filed Sept. 22, 1964 'n1nnulllulllllllllln M M E Dec. 23, 1969 c. VAN DER LELY 3,484,999

PREFABRICATED SECTION OF A WALL, FLOOR OR ROOF Original Filed Sept. 22., 1964 16 Sheets-Sheet 6 8 M 76 xtX Ni 67 67 c x INVENTOR. CORNE'L 1s VAN DER [ELY 1959. c. VAN DER LELY 3,484,999

PREFABRICATED SECTION Of A WALL, FLOOR OR ROOF Original Filed Sept. 22, 1964 16 Sheets-Sheet 7 INVENTOR. cgmvsuo' VAN 05/? ELY 23, 1969, c. VAN DER LELY 3,484,999

PREFABRIGATED SECTION OF A WALL, FLOOR OR ROOF Original Filed Sept. 22, 1964 16 Sheets-Sheet 8 6 4 THIN &J 0 A 3 w U M v H w 8/ f n m E. Q? U I 2 f aim M1 T. w a F L a 3 A L/LH JL fi 2 a m7? m 5 m: T f: M Z, fl l 2 L 4, 1 fl 4 w 1 /W m a w n fi l PM J INVENTOR. COP/WE'LL? KAN DER ZELY Dec. 23, 1969 c. VAN DER LELY 3,484,999

PREFABRICATED SECTION OF A WALL, FLOOR OR ROOF Original Filed Sept. 22, 1964 16 Sheets-Sheet 9 INVENTOR. a /v50: VAN 0:51? [51. Y

Dec. 23, 1969 VAN DER LELY 3,484,999

PREFABRICATED SECTION OF A WALL, FLOOR OR ROOF Original Filed Sept. 22, 1964 16 Sheets-Sheet 1O INVENTOR. CORNEL/J VAN DE}? [1514 a r/mg J Dec. 23, 1969 VAN DER LELY 3,484,999

PREFABRICATED SECTION OF A WALL, FLOOR OR ROOF Original Filed Sept. 22, 1964 16 Sheets-Sheet 11 nx1111r111z41 r r u I I f Y 5.- a as INVENTOR. COR/VEL/J ww use ZELY Dec. 23, 1969 c. VAN DER LELY PREFABRICATED SECTION OF A WALL, FLOOR OR ROOF Original Filed Sept. 22, 1964 16 Sheets-Sheet l2 w o 'e m %m E F fi F W 0/ 7 a A. a. 8 3 Wm a w 2 W a 0 EB J N 7 0 0 6 a 6% 2 6 a. n a

a 2 a M 3 u 2 1969 c. VAN DER LELY 1 3,484,999

PRE FABRIGATED SECTION OF A WALL, FLOOR OR ROOF Original Filed Sept. 22, 1964 16 Sheets-Sheet is Tag INVENTOR. camvfi'us v /v use [51. V

WZamr, fwm 9 Dec. 23, 1969 O LELY 3,484,999

PREFABRICATED SECTION OF A WALL, FLOOR 0R ROOF CORNELL? VAN DE? [51? Off? Dec. 23, 1969 c. VAN DER LELY v 3,484,999

PREPABRICATED SECTION OF A WALL, FLOOR OR ROOF Original Filed Sept. 22, 1964 16 Sheets-Sheet 15 FTQ. 36

' INVENTOR. ap/v54 m" mm 051? [m Dec 23, 1969 c. VAN DER LELY PREFABRICATED SECTION OF A WALL, FLOOR OR ROOF l6 Sheets-Sheet 16 Original Filed Sept. 22, 1964 INVENTOR. CO/QNEL/J VAN OED LEL V United States Patent ABSTRACT OF THE DISCLOSURE Reinforced concrete slab for the floor or root of a prefabricated building element, the slab being surrounded by frame of channel beams, the upper limb of the channel beams being embedded in the slab and having its upper face coplanar with the slabs face, a plurality of metal ribs partly embedded in the slab and connected to the reinforcing member in the slab and to the frame of channel beams.

SUMMARY OF THE INVENTION This application is a continuation of application Ser. No. 398,234 filed Sept. 22, 1964.

The invention relates to a prefabricated section of a wall, floor or roof, comprising a slab of concrete or like material. 1 t

The invention has for its object, inter alia, to provide a prefabricated section of the kind mentioned above, the weight of which may be light as compared with its load capacity and which is readily transportable.

In accordance with the invention this can be achieved by providing the concrete slab on one side face with a plurality of ribs which are secured to the slab distributed thereover at a small distance from each other, said ribs being made independently of the concrete slab and being capable of withstanding stress or pressure or both. The ribs assume a large portion of the load capacity of the section and for such reasons are spaced closely together, e.g. separated by a maximum distance of 100 centimeters. An advantageous embodiment of the section according to the invention is obtained by embedding the ribs partly in the concrete slab.

The structure of the section is improved, in accordance with the invention, by providing the concrete slab with a connecting member and securing the connecting member to the ribs. In an advantageous embodiment of the invention the concrete slab has a thickness of between 2.5 and 6 centimeters.

According to a further aspect, the section according to the invention constitutes a wall, floor or roof of a boxshaped section enclosing a space which is provided with further walls, a roof and/or a floor. Because of the construction involved, the erection of a building is improved.

According to a still further aspect of the invention, the concrete slab is provided at its periphery with metal beams. By reason of the construction involved the section is made stronger and the beams provide protective means, especially protecting the edges of the section from damage.

An advantageous embodiment can be'obtained when the ribs are made of metal.

According to a yet further aspect, the section according to the invention forms at least a part of a bottom or roof, whereby on the upper side the concrete slab is provided with a covering sheet of insulating material, which is secured to the concrete by casting the latter. The sec- Patented Dec. 23, 1969 tion can therefore be elfectively employed in buildings in which the insulating material serves both for thermal insulation and for sound insulation.

The invention furthermore relates to a method of manu-' facturing a section according to the invention, in which the ribs are disposed on a jig, whereby the sides of the ribs to be connected with the concrete are disposed to face the jig and are subsequently cast while on the jig with the ribs being embedded in one side in the concrete.

A simple method consists in that, subsequent to casting of the concrete in its moist state, the insulating material which is to be disposed between the ribs is urged at least partly against concrete slab, so that it will stick to the concrete after the concrete has hardened.

The invention relates to a further house comprising only one story and erected by means of prefabricated boxshaped sections which are composed at least partly of concrete or like material and which each enclose at least part of a living space whereby, according to the invention, the house consists in principle of only two box-shaped sections which are parallelepiped-shaped and of which the walls, bottom and/or roof are made of concrete having a thickness of between 2 and 6 centimeters. 'In this manner a strong structure is obtained, whereas its weight may be small.

For a better understanding of the invention and to show how the same may be readily carried into effect, reference is made by way of example to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a prefabricated floor section, which is provided at its periphery with a metal mm.

FIG. 2 shows on an enlarged scale a detail of the section shown in FIG. 1, viewed in the direction of the arrows IIII.

FIG. 3 shows on enlarged scale an elevation of the element shown in FIG. 1 in the direction of the arrows III-III.

FIG. 4 shows a detail corresponding with that of FIG. 2 of a further embodiment of the invention.

FIG. 5 shows a detail of a section according to the invention, which corresponds with the detail of FIG. 3, but this section has an insulation on its bottom side.

FIG. 6 is a perspective view of part of a box-shaped section in which the floor section according to the invention is arranged.

FIG. 7 is a perspective view of a bungalow erected from box-shaped sections of the kind shown partly in FIG. 6.

FIG. 8 is a perspective viewof a section according to the invention.

. FIG. 9 shows on an enlarged scale a sectional view of a rim of the section of FIG. taken on the line IX.IX. FIG. 10 shows on an enlarged scale a sectionalviewvof. the section of FIG. 8 taken on the line X-X. l FIG. 11 is a sectional view corresponding with that of FIG. lOwith the ribs having,.however, a shape differing from that of FIG. 10. i

FIG. 12 shows on an enlarged scale a sectional view corresponding with that of FIG. 10, the ribs of the sec; tion having, however, a different shape.

FIG. 13 is a sectional view corresponding with that of FIG. 10 of a different embodiment of a section according to the invention. q p p FIG. 14 shows on an enlarged scale a'sectionalview corresponding with that of FIG. 10, thejribshaving a different shape.

FIG. 15 is a sectional view of .a diliereht embodiment.

of a rim of the section according to theinvention. FIG. 16 is a perspective view ofv a garage according to the invention.

FIG. 17 is a horizontal sectional view of a side wall of the garage taken on the line XVII-XVII in FIG. 16.

FIG. 18 shows a plan of a house according to the invention.

FIG. 19 is a perspective view of the house of FIG. 18.

FIG. 20 is a sectional view taken on the line XXXX in FIG. 18.

FIG. 21 is a sectional view taken on the line XXI-XXI in FIG. 18.

FIG. 22 shows, on an enlarged scale, the upper side of a section in a sectional view.

FIG. 23 shows on an enlarged scale part of the roof joints of the two sections, in the direction of the line XXIII-XXIII in FIG. 19.

FIG. 24 shows part of the roof arranged above a section, viewed in the direction of the line XXIV-XXIV in FIG. 19.

FIG. 25 shows on an enlarged scale a horizontal sectional view of part of a section taken on the line XXV-XXV in FIG. 19.

FIG. 26 shows on an enlarged scale a sectional view of the fastening of two sections to each other taken on the line XXVIXXVI in FIG. 21.

FIG. 27 is a horizontal sectional view of a connecting part of the sections taken on the line XXVII-XXVII in FIG. 21.

FIG. 28 shows on an enlarged scale a sectional view of adjacent lower sides of the sections taken on the line XXVIII-XXVIII in FIG. 18.

FIG. 29 shows a plan of a house according to the invention the arrangement of which differs from that of FIG. 18.

FIG. 30 shows a plan of a further variant of the construction of the house according to the invention.

FIG. 31 is a perspective view of a bungalow erected from a plurality of sections manufactured according to the invention.

FIG. 32 is a perspective view of a frame of a section of the building shown in FIG. 31.

FIG. 33 shows on an enlarged scale a sectional view taken on the line XXXIII-XXXIII in FIG. 31 for the roof edges of two adjacent sections.

FIG. 34 shows on an enlarged scale a sectional view taken on the line XXXIV-XXXIV in FIG. 31 over part of the roof edge of a section.

FIG. 35 is a sectional view of part of the roof taken on the line XXXV--XXXV in FIG. 31.

FIG. 36 is a plan view of the structure of the ceiling, the roof covering being omitted.

FIG. 37 is a perspective view of part of the ceiling structure of FIG. 36.

DESCRIPTION OF THE PREFERRED,

' I EMBODIMENT FIGS. 1, 2 and 3 show a section comprising a slab 1 of foam concrete of a thickness designated by reference numeral 2. The concrete slab 1 is provided on the bottom side with a number of metal ribs 3, having a height designated by reference numeral 4. The metal ribs 3 are made of thin sheet material of a thickness designated by reference' numeral 5. On the upper side each rib 3 is provided with aportion which extends perpendicularly thereto a distance designated by reference numeral 6 and on the bottom side with a further portion which similarly extends perpendicularly thereto a distance designated by reference numeral7. The upper side of the metal rib 3 is embedded in the concrete of the slab 1 over a distance designated by reference numeral 8, which is approximately V12 of the height 4. The metal ribs 3 are parallel to each other and are spaced apart from each other by a distance designated byreference numeral 9. The thickness 2 of the concrete slab 1 is preferably less than 6 cms. and is in this embodiment 4 cms. The height 4 of theribs 3 is 12 cms. and the thickness is at the most 5 mms., and p efe a y 3 as in the embodiment shown. The dimension of bent-over portion 6 is about 8 mms. while that of bent-over portion 7 is about 25 mms. The distance 9 between the metal ribs is less than cms. and preferably about 50 cms.

The metal ribs 3 are provided with a layer 10 of anticorrosive material. On the upper sides the metal ribs 3 have a connecting member 11, which is embedded in the concrete slab 1 and is secured by spot welding to the upper side of the metal ribs. The connecting member 11 consists of a network or wires 12 extendingin the longitudinal direction of the section and wires 13 extending transversely of the longitudinal direction, said wires having a thickness designated by reference numeral '15 of about 3 mms. The wires 12 and 13 are spaced apart from each other by distances designated by reference numeral 14 of about 30 cms. The upper sides 16 of the metal ribs 3 are not provided with anti-corrosive material in order to permit of welding the connecting member 11 thereto.

On the long sides the section is provided with rims 18 and 19, which are located on opposite peripheral sides of the concrete slab. The rims 18 and 19 are formed by metal U-section beams of Npl6. The metal ribs 3 are located between the rims 18 and 19 and extend at right angles thereto. The ends of the metal ribs 3 are welded by their lower sides to the lower limb 21 of the rims by spot-welding. The ends of the metal ribs extend over a distance designated by reference numeral 24 between the lower limb 21 and the upper limb 22 of each of the channel-section beams 18 and 19, and area distance as indicated by reference'numeral 25 from the webs of the beams, which it is to be seen is approximately equal to the distance 24. r

The beams 18 and 19 have a length designated by reference numeral 20, which is equal to the length of the section. The beams 18 and 19, like the metal ribs 3, are provided with a layer 26 of anti-corrosive materal. The beams 18 and 19 are provided with holes 27 through which connecting means can be taken in order to interconnect adjacent sections. The short sides of the section are provided with rims 28 and 29, the ends of which are connected with the rims 18 and 19 so that the whole section is provided along its periphery with a metal rim. Also the rims 28 and 29 are formed by channel-section beams of Npl6. The width as indicated by reference numeral 30 of the section is about 2.5 meters, and the length 20 is about 11.5 meters.

The structure as described above provides a solid light weight section. The section can be readily prefabricated and subsequently it can be easily transported, owing to the light weight and the solid structure, to the the site where the section has to form at least part of a floor. The section may be employed for all kinds of floors, for example in buildings as a floor or a roof or in bridges. In arranging the section in place, the rims 18 and 19 may be supported at one or more spots between the ends.

The section can be fabricated in a simple manner by arranging the metal strips parallel to each other and by interconnecting them by means of the connecting member. The ends of the metal ribs can be secured to the rims 18 and 19, while the rims 28 and 29 may be secured in the same manner. The assembly can then be arranged on a jig so that the upper ends of the metal ribs are on the bottom side; then the concrete can be cast. The concrete can be cast on a vibrating table where the concrete is vibrated to obtain a compact structure.

Prior to casting of the concrete the various parts may be provided with anti-corrosive material. The rims 18 and 19 and the rims 28 and 29 may, for example, be first secured to each other with the ribs 3, the assembly being then dipped in a bath of anti-corrosive material, for example Innertol. Subsequently, the upper edges of the ribs can be partially cleaned in order to permit of. secur ing the connecting member 11. If desired, the connecting m mb r 11 m y be s cured to he ribs 3, the anti-co ro sive material being applied, for member, ribs and edges.

FIG. 4 shows a detail of an embodiment corresponding in principle with the embodiment shown in FIGS; 1 to 3. However, the upper side of the concrete slab is provided here with an insulating layer 31. The parts corresponding with those of the preceding figures are designated by the same reference numerals. The layer of insulating material 31 consists of a thin,resinous hardboard sheet, which is secured to the concrete by casting. The rims 31 extend over the limb 22 of the rim 19 and the corresponding limbs of the rims 18, 28 and 29. The coating of anti-corrosive material applied to the upper side of the limb 22 serves as a flexible layer promoting a satisfactory connection of the rims of the insulating material to the rims of the section.

In manufacturing -a section as shown in FIG. 4, the layer of insulating material 31 may be disposed on the jig prior to casting the concrete slab, the frame of the rims and of the metal ribs being subsequently disposed on said jig and the concrete slab being then cast. The insulating layer 31 may serve simultaneously for heat insulation and sound insulation.

FIG. 5 shows an embodiment in which the section is provided with insulating material on the bottom side. The part corresponding with those of FIG. 3 are noted in FIG. 5 by identical reference numerals. The section shown in FIG. 5 is provided on the bottom side with strips 32 of insulating material, the width designated by reference numeral 33 being such as to be somewhat greater than the distance between the metal ribs 3. The layer of insulating material 32 is formed by strips, the length of which is equal to the width of the section. Each of the strips 32 bears with the upper side 34 of the bent-over edge 17 of the metal ribs, whereas the edge 35 is located beneath an edge 17 of a metal rib. The edges 17 are gripped by clamping members 36, one limb 37 of which is located above the edge 17 and one limb 38 of which is located beneath such edge. The upper limb 37 bears on the edge 17 and the edge 34 of the sheet 32 is located above said limb. Between the edge 17 and the lower edge 38 of the clamping member 36 there is clamped the edge 35 of the strip of insulating material. The strips of insulating material 32 may be formed by soft board or other suitable cheap or light-weight material.

FIG. 6 shows part of a box-shaped section bounding at least part of one or more living rooms. The section shown in FIG. 6 is provided at the bottom with a floor section 39 of the structure shown in any of the preceding figures. Said section is built up by fastening vertical beams 40 to the rims 18, 19, 28 and 29, the upper ends of said beams being secured to a rectangular frame of beams 41, 42, 43 and 44. A section of the kind shown in FIG. 6 may be completely prefabricated and during the prefabrication process Wall portions may be secured to the vertical beams 40, and the lower portion 39, and the beams 41, 42, 43 and 44, said walls forming partitions between the various spaces of the building erected from box-shaped sections of the kind shown in this figure. In this figure, however, no partitions are shown.

FIG. 7 is a perspective view of a bungalow comprising box-shaped sections of the kind shown in FIG. 6. The bungalow comprises five sections 45, 46, 47, 48 and 49, the long sides of which are secured to each other.

The sections can be secured to each other by using the holes in the rims of the lower section 39, for example the holes 27 and the corresponding holes in the frame of beams 41 and 44 and by inserting fastening bolts through said holes.

The embodiment shown in FIGS. 8, 9 and 10 is a plateexample by dipping, to the shaped section which is provided at the periphery with.

flange beams formed by metal channel-section beams. The section is rectangular and has a length designated by reference character 51B and a width 51A designated by reference character of about 10 meters and about 2.5

meters respectively. FIG. 8 shows two flange beams 52 and 53. The section 51 comprises a slab 54 of foam concrete having a thickness as shown by reference character 55 of between 2.5 cms. and less than 6 cms.; in this embodiment it is about 4 cms. The slab 54 is supported from Wooden, rectangular-section ribs 59, which extend at right angles to the long sides of the section and are parallel to each other. As compared with the size of the section the ribs are arranged at a short distance from each other and in this embodiment at a distance indicated by dimension 60 of about 50 cms. Preferably the distance between the ribs is preferably will not exceed cms. FIG. 10 shows two adjacent ribs, with part of the slab between these ribs is interrupted. However, with a view to the rigidity to be imparted by the ribs to the slab, the ribs will usually not be spaced apart from each other by more than 1 meter. The ribs 59 have a height as indicated by reference numeral 61 of about 15 cms. and a thickness of about 4 cms., designated by reference numeral 62. The ribs 59 are embedded, as shown in the figures, with their upper parts over a distance as shown by reference numeral 61A of about 2 cms. in the concrete of the slab 54. The part of the ribs 59 embedded in the concrete is provided with a moisture-repelling layer 63. Inside the slab 54 there is provided a connecting member 56, which is formed by a network of circularsection metal wires 57 having a diameter, designated by reference numeral 58, of about 3% mms. The width of mesh is preferably not more than 8 cms., and in this embodiment it is 5 x 5 cms. The connecting member is located centrally of the direction of thickness of the concrete slab 54. The ribs 59 are arranged with their ends between the limbs of the flange beams arranged along the long sides of the section, for example between the limbs 64 and 65 of the beam 52 (see FIG. 9). The ends of the ribs 59 may, if desired, be secured to joists 66 provided between the limbs 64 and 65. The limb 65 of the beam 52 and the corresponding limbs of the further flange beams are substantially completely embedded in the concrete. The connecting member 56 is connected with the flange beams for example by spot-welding and with the ribs 59 by means of cramps 59A. The upper ends of the ribs are embedded in the slab 54 over more than half the thickness thereof. The slab 54 is provided on the side remote from the ribs with a layer 67 of insulating material, which consists, in the embodiments shown in FIGS. 8, 9 and 10, of a layer of cork. To the layer 67 are applied coatings 68. The layer 67 has a thickness, designated by reference numeral 69, of about 2 cms. Between the ribs 59 the lower side of the slab 54 is provided with a layer of insulating material 70, for example of glass wool, which includes portions 71 to cover the sides of ribs 59. On the lower side of the ribs 59 there are secured covering sheets 72, composed of suitable material, for example, hardboard.

By using the structure according to the invention a section is obtained, the weight of which is light as compared with its load capacity. The section can be readily manufactured in the workshops. First a frame of two longitudinal beams 52 and two transverse beams is made, the ribs 59 being secured thereto. The network 56 is fastened to one side of the flange beams and of the ribs, after which the assembly is disposed with the network turned downwards in a jig, in which the slab 54 can be cast. Before casting the concrete, the metal parts and the sides of the ribs to be embedded in the concrete may be provided with an anti-corrosive layer. The various parts may, if desired, also be made of stainless material. On the bottom of the jig there may be disposed the cork layer 67, the concrete being cast on said layer. The concrete will adhere satisfactorily to the cork layer 67 and the connecting member 56, and the parts 61A of the ribs 59 are thus embedded simply and effectively in the concrete. Before the concrete of the slab 54 has hardened, the insulating material 70 is applied to the still soft concrete, and is particularly pressed tight along the ribs against the concrete so that, when the concrete hardens, the layer 70 sticks to the concrete. The covering sheets 72 can be secured to the lower sides of the ribs remote from the connecting member 56 and subsequent to the removal from the jig, the covering layer 68 can be applied to the cork layer 67.

A section of the kind described above may be used effectively, for example, as a roof portion, in which case the various layers of insulating material provide a satisfactory heat insulation and sound insulation. The sheets 72 may serve in this case as the ceiling of the space covered by the slab on the upper side. A section of the kind shown in FIGS. 8, 9 and 10 may be employed in a simple manner in box-shaped sections having several walls. and bounding at least part of the space inside a building. In this case the beams at the peripheral edges, for example the beams 52 and 53, may form, if desired, part of a metal skeleton of a prefabricated box-shaped section with said skeleton supporting walls, and with at least part of the roof and floor of a building formed from one or more prefabricated sections.

With the structure of the section comprising a large number of ribs evenly distributed over the slab and capable, in principle, of withstanding the major part of the forces exerted on the section, the slab 54 may have a small thickness. As a result, the concrete slab 54 can be loosened easily from the jig whereas the same will dry rapidly after casting and promptly be removed from the jig, so that the manufacturing process in the workshops takes little time and long drying periods of material and a great number of jigs are dispensed with.

FIG. 11 shows an embodiment in which the section is constructed in the same manner as in the preceding embodiment except that the ribs 59 are replaced by Wooden ribs 73, having a sectional area which is trapezoidal. Parts corresponding with those of FIGS. 8, 9 and 10 are designated by the same reference numerals as in the first embodiment. The ribs 73 have a height as shown by the dimension 73A of about 12 cms. The small parallel sides embedded in the concrete have a width dimension 73B of mms. and the other larger side has a width dimension 73C of 75 mms. Although this is not indicated in FIG. 11, a layer of insulating material may be applied to the lower side of the concrete slab, and to the lower side of the ribs 73 there may be applied a cover of hardboard or soft board. In certain cases it may be more advantageous to secure covering sheets to the wider lower sides of the ribs 73.

FIG. 12 shows an embodiment in which the ribs 74, which support the concrete slab, are made of metal having a thickness designated by reference numeral 75 of about 3 to 4 mms. The height of the metal ribs 74 is equal to the height of the ribs 73. Parts shown in FIG. 12 which correspond with parts in the preceding embodiments are denoted by the same reference numerals. The metal ribs 74 are spaced apart from each other by distances corresponding with the distance 60 of FIG. 10. On one upper side of the ribs 74 there is provided a bent-over rim 76 and on the other side there is a further rim 77. The rims 76 and 77 extend to different sides of the ribs and the rims 76 are completely embedded in the concrete. Also in the structure shown in FIG. 12 the bent-over rims 77 of the ribs 74 may be provided with covering sheets like the sheets 72 of FIG. 10, but this is not shown in the figure. The sections according to the invention may be used without covering sheets or ceiling sheets 72. Before the concrete slab is cast, the metal ribs 74 may be provided with an anti-corrosive layer. Particularly with the use of metal ribs it may be important to have the layer of insulating material 70 prolonged along the ribs in order to avoid absorption and conduction of cold or heat through the ribs.

FIG. 13 shows an embodiment of a section consisting of a slab 78 of concrete, in which a reinforcement network 79 is provided, which may be formed in the same manner as the member 56 of FIG. 9. The slab 78, like theconcrete slabs in the preceding embodiments, has a thickness designated by reference numeral 80 of about 4 cms. The ribs on the slab 79 in this embodiment are formed by a strip 81 of channel-sectional area, having limbs 82 and 83, the ends of which are embedded in the concrete slab 78. The ends of the limbs 82 and 83 are provided wit-h rims 84 and 85 bent-over towards the outer sides of the channel-section strip 82. Between the limbs 82 and 83 and the web 86 of the channel-section strip 81, the space 87 is filled out with concrete which is integral with the slab 78. In this embodiment the slab 78 is provided on the side opposite the ribs 81 with ornamental strips 88, which can be secured to the slab 78 during the casting operation. The ornamental strips or plates 88, like the cork layer 67, of the first embodiment, may be disposed on the bottom of the jig, the concrete being subsequently cast thereon. The ornamental plates 88 may be used particularly successfully when the sections form walls, in which case the ornamental plates 88 may constitute facade ornaments. The channel-section ribs 81 may be spaced apart from each other by the same distance as the ribs 59 (FIG. 10) or at a slightly larger distance. When the section is used for a wall, the ribs 81 may be arranged at a slightly larger distance from each other than in the case of using the section as a supporting floor. When used as a wall section, the height of the ribs need not be so great as in the case in which the section serves as a supporting floor. In FIG. 13 the ribs are lower than in the preceding embodiments and they have a height designated by reference character 81A of about 4 cms., while the web 86 has a width of about 6 cms.

The embodiment shown in FIG. 14 corresponds with the embodiment shown in FIG. 11 and similar parts are designated by the same reference numerals. In the embodiment of FIG. 14, the ribs 73 are replaced by concrete ribs 89, which are provided with reinforcement 90. The ribs 89 are made independently of the slab 54 and are embedded therein when the slab 54 is cast. A waterrepellent layer like the layer 63 (FIG. 10) around the rib 73 may be omitted when the concrete rib 89 is employed. The concrete ribs, like the ribs of the preceding embodiments, may be arranged on the peripheral edges of the section. The use of concrete ribs is particularly successful when the ribs are exposed to moisture, so that they may be of great importance when the section is used in a floor.

FIG. 15 shows a structure in which the peripheral edges of the section are formed in a manner differing from that shown in FIGS. 8 and 9. In the embodiment shown in FIG. 15, the peripheral edge is formed by a concrete rim 91, which is stuck to the slab 54 during casting and which is integral herewith. The ribs 92 are cast in the concrete rim 91 and, as in the preceding embodiments they may be made of wood, metal or concrete. The peripheral rim 91 in the embodiment of FIG. 15 is provided with a portion 93 which projects above the upper side of the concrete slab 54 including the insulating layer 67 and the cover 68. This construction may be advantageously used when the section forms a roof portion, in which case the rim 93 constitutes an upright roof edge, and the water is prevented from leaving the roof except at those places thereon where draining pipes or the like are provided. The construction shown in FIG. 15 may also be used in box-shaped sections, in which case the rim 91 may form the upper side of a side wall of the section as is shown in- FIG. 15. The side wall 91 may then be built up in the manner shown in FIG. 13.

The building according to the FIGURES l6 and 17 forms a garage and is built up of only one prefabricated section which is supported from prefabricated foundation beams 102 and 103. The prefabricated section 101 comprises a roof 104, a floor 105 and side walls 106, only one of WhlCh is shown in FIG. 16. The section furthermore 

